Vanda seeming to suddenly loose leaves
 

My vanda was doing well, or so I thought. It had eleven flowers from November till they dropped on Monday this week. It also appeared to be growing and over the summer had root growth.

It is potted, which I know is unusual but seems to be done more often in the UK. It had done well that way since I bought it in March last year. I water very sparingly by dribbling a little through the bark each day, as advised by someone on OB who grows them the same way.

When I came to move it after flowering I noticed a worrying yellow at the base of the lowest leaves. I'm not sure how long it had been like that. These lowest leaves also showed signs of wrinkling. Not sure if either the yellow or the wrinkling shows up in this pic I took yesterday.

http://lh5.ggpht.com/_o4OXVkcS2VU/TU...%20%284%29.JPG

Today when I came to look closer while watering one of the leaves fell off in my hand. Then I found that just gentle handling of others caused them to just fall away with no effort. It lost 8 of it's 16 leaves and I'm not sure about the lowest two remaining ones.

http://lh6.ggpht.com/_o4OXVkcS2VU/TU...Jan%202011.JPG

There are two major diffences recently. It has been in dim light since December because I had it in a position where I could see the blooms well, but was not ideal for giving it light. The other difference is that all through January I have not been keeping up with any orchid watering very well, and my records show an average of every 3 days with only a dribble of water rather than every day (it went longer a couple of times).

I kind of hope it is either the water or light because that is easy to correct, but I'm worried it's something else. The roots as far as I can see are fine there are some good fat healthy roots on the surface of the medium. There are also good healthy looking roots further down visible through the side.

My book on vandas states that too little light or too little water and humidity are the most common reason for leaf loss on vandas. Maybe a humidity tray would help.

Thanks Tucker.

On this thread Carol suggests cold can also cause it. Which reminds me that we had heating failure a couple of weeks ago. I moved all the warm loving plants including the Vanda to the only room we could heat, but the temp still dropped lower than normal several times. All the others (phals, dens, paphs) have been fine although I've had some bud blast accross most genuses which I put down to that.

I have also had rot suggested. I can't see any sign but I'm not ruling it out.

So that's water, light, cold which are all possibilities which I know have happed, as well as rot. I hope it's more like the first 3 than the rot :crossfing

1st, does it have Vanda coerulea in the heritage?

If it does, it can handle cold down to 36 F for short periods of time on occasion.

2nd, does it dry out between waterings?

It should.


To add to what "tucker85" had said, yes, they do lose leaves when the humidity is too low, or if they don't get enough water as well. As was mentioned, low light levels will do it too.

Make the necessary adjustments, and it will bounce back almost immediately.

There's no rot going on.

Thanks Philip.

It's a complex hybrid which works out as 25% coerulea (coerulea is scattered all over it's parantage). It's 60% sanderiana with luzonica, dearei and tricolor making up the other 15%. So I guess it should be able to cope with the brief cold.

It's pretty dry most of the time with a dribble of water each watering (actually I spray the surface roots and a very little dribbles down from that). I used to do this daily, but have been struggling to keep up with my orchids though Jan so it's been drying far more.

One of the reasons for growing in bark is meant to be that it keeps the humidity arround the roots higher, which of course will be less with it drying more. Also it's been in the living room since mid december with the central heating drying the air. Usually it was in the kitchen on a windowledge over the sink and I think even with the heating that position is more humid.

Anyway, it's now back over the kitchen sink. That is one of the brightest windows in the house. We don't get much sun at this time of year but it will get a lot more than in the living room. It will also get the humidity from the sink, and I'll really push to water it more often again. It was happy in that spot from March to May last year (then moved outside) and from September to December after it came back in, so hopefully it will like that again.

Thanks for the advice!

Rosie,

this could be a number of things. The roots were too wet for too long due to being potted in substrate and rotted over winter. In that case, the remaining root system would not be able to support the leaves any more. Or it could be that the substrate started to break down, the roots stay too wet and/or don't get enough air, with the same effect. Or Fusarium wilt having infected the roots: low light in the northern hemisphere and low humidity can make plants susceptible to Fusarium.

If the issue was with humidity, I think the leaf drop would have been less rapid.

Lars

Thanks Lars,

Well I think I will just have to see how it goes. It's nowhere near other orchids in it's current/usual spot. If it dies I'll just have to try again with another one ;)

Would be a shame if it died, the blooms were pretty.

It is too easy to over water during the winter, with less air movement and sunshine. I let my Vanda almost dry out between waterings, but mist in between. My guess is, just as Lars said. The medium is likely rotting, since it can't dry out between waterings.